1. Field of the Invention
The present invention relates to a vapor generation system and process utilizing an inert gas stream for aspirating a liquid and conveying a vaporous mixture to a processing unit. More particularly, the invention is directed to a vapor generation system using heating and aspiration for conveying a resultant vaporous mixture against a workspace, such as a conveyor metal surface having silicon dioxide (SiO.sub.2) contamination thereon, so as remove such contamination.
2. Description of the Related Art
Contamination of semiconductor manufacturing equipment which convey semiconductor wafers into a processing chamber have continued to be a processing problem. In atmospheric-pressure chemical vapor deposition (APCVD) equipment, a transport conveyor, typically a stainless steel conveyor belt, conveys semiconductor wafers into and out of a APCVD chamber. Heretofore a so-called "muffle chamber" has been employed next to the APCVD chamber where a continuous-belt type conveyor is cleaned prior to receiving as-received wafers for additional APCVD processing. In a CVD process, performed either at atmospheric pressure or at a low pressure i.e., at a medium vacuum of 0.25-2.0 torr, at a temperature of 550-600.degree. C., various deposits of SiO.sub.2 are deposited, not only on the wafers as prescribed by the chip design, but also on the conveyor belt itself. As the SiO.sub.2 deposits build up, SiO.sub.2 particulates can flake-off the belt and cause contamination of the wafers in the CVD reaction chamber. SiO.sub.2 is formed in the CVD reaction chamber typically by the reaction of a silane and excess oxygen by a heterogeneous surface reaction. Homogeneous gas gas-phase nucleation can occur leading to small white powdery SiO.sub.2 particles on the chamber walls and on the conveyor belt, which can cause the particulate contamination in the deposited films on the wafers. Thus, improved apparatus for cleaning a continuous belt conveyor is desirable to eliminate this source of contamination.